A prospective, single-center study to evaluate the clinical performance of Meril ABFind in individuals vaccinated against COVID-19

Background: Accurate rapid antibody detection kits requiring minimum infrastructure are beneficial in detecting post-vaccination antibodies in large populations. ChAdOx1-nCOV (COVISHIELD) and BBV-152 (Covaxin) vaccines are primarily used in India. Methods: In this single-centre prospective study, performance of Meril ABFind was investigated by comparing with Abbott SARS-CoV-2 IgG II Quant (Abbott Quant), GenScript cPass SARS-CoV-2 neutralization antibody detection kit (GenScript cPass), and COVID Kawach MERILISA (MERILISA) in 62 vaccinated health care workers (HCW) and 40 pre-pandemic samples. Results: In the vaccinated subjects, Meril ABFind kit displayed high sensitivity of 93.3% (CI, 89.83%-96.77%), 94.92% (CI, 91.88%-97.96%), and 90.3% (CI, 86.20%-94.4%) in comparison to Abbott Quant, MERILISA, and GenScript cPass respectively. The results of the Meril ABFind in the COVISHIELD-vaccinated group were excellent with 100% sensitivity in comparison to the other three kits. In the Covaxin-vaccinated group, Meril ABFind displayed sensitivity ranging from 80% to 88.9%. In control samples, there were no false positives detected by Meril ABFind, while Abbott Quant, MERILISA, and GenScript cPass reported 2.5%, 10.0%, and 12.5% false positives, respectively. In the pre-pandemic controls, specificity of Meril ABFind was 100%, Abbott Quant 97.5%, MERILISA 90%, and GenScript cPass 87.5%. Conclusion: The Meril ABFind kit demonstrated satisfactory performance when compared with the three commercially available kits and was the only kit without false positives in the pre-pandemic samples. This makes it a viable option for rapid diagnosis of post vaccination antibodies.

Comparison of Clinical, Immunological And Radiological Characteristics In Autoimmune GFAP Astrocytopathy, MOGAD And AQP4-Igg +NMOSD Mimicking Infectious Meningitis As The Initial Manifestation

Objective: Several autoimmune CNS inflammatory diseases, including autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and aquaporin-4-immunoglobulin-G-positive neuromyelitis optica spectrum disorders (AQP4-IgG+ NMOSD) often presented initially with similar infectious meningitis-like symptoms. However, it was not easy to differentiate them at disease onset without antibody detection. The present study aimed to compare the clinical, immunological and radiological features among the three diseases. Methods: In our single-center cohorts, 9 A-GFAP-A, 17 MOGAD and 11 AQP4-IgG+ NMOSD patients mimicking infectious meningitis as initial symptoms were retrospectively included. The autoantibodies were detected with cell-based assays. The clinical, immunological and radiological characteristics of the three groups were summarized. Results: AQP4-IgG+ NMOSD patients were statistically more often in men (10, 90.9%, P=0.003). Tremor was predominated in A-GFAP-A (4, 44.4%) over MOGAD (1, 5.9%, P= 0.034) and never found in AQP4-IgG+NMOSD (0, P=0.026). The Modified Rankin Score (mRS) at the clinical nadir of diseases was lower in AQP4-IgG+NMOSD (2.2 [IQR, 1-3]) compared to A-GFAP-A (3.7 [IQR, 3-5], P=0.04). On CSF examination, white blood cell count (WBC) was higher in A-GFAP-A (median, 272×106/L [range, 0-1600]) compared to AQP4-IgG+NMOSD (median, 12×106/L [range, 0-48], P=0.049). Significant increase in CSF protein (1490.7±871.2 mg/L), lactic acid (3.43±0.81 mmol/L), IgG (130.9±60.4 mg/L), IgM (8.6±6.1mg/L) and IgA (23.0±11.4mg/L) levels in A-GFAP-A was found compared to MOGAD (CSF protein: 606.7±379.4 mg/L, P<0.001; lactic acid: 2.15 ± 0.62mmol/L, P<0.001; IgG: 77.9±71.3 mg/L, P=0.043; IgM, 2.7±2.9mg/L, P=0.002; IgA, 11.3±12.1mg/L, P=0.012) and AQP4-IgG+NMOSD (CSF protein: 441.8±178.0 mg/L, P<0.001; lactic acid: 2.40 ± 0.66 mmol/L, P=0.003; IgG, 53.2±30.3 mg/L, P=0.01; IgM, 2.1±3.9mg/L, P=0.003; IgA, 5.2±5.0mg/L, P=0.001). Over half of the A-GFAP-A patients (5/8, 62.5%) showed small (<2 cm), symmetrical lesions in ganglia and thalamus (5/8, 62.5%), but never in MOGAD (0%, P=0.001) and AQP4-IgG+NMOSD (0%, P=0.026). Diffuse meningeal enhancement was common in A-GFAP-A (8, 88.9%) compared to MOGAD (5, 29.4%, P=0.011) and AQP4-IgG+NMOSD (1/6, 16.7%, P=0.011). Acute disseminated encephalomyelitis (ADEM) -like lesions occurred frequently in MOGAD (6/16, 37.5%) but never in A-GFAP-A and AQP4-IgG+NMOSD (P=0.02). Conclusion: Our study demonstrated that several signs including the symptom of tremor, a more severe disease course, higher CSF immunological profiles and ganglia bilateral symmetrical lesions, diffuse meningeal enhancement were distinct features in A-GFAP-A, and ADEM-like lesions occurred only in MOGAD mimicking infectious meningitis as initial symptoms, providing possible clinical implications for patient differential diagnosis.

Persistent T-Cell Reactivity in a Seronegative Patient after SARS-CoV-2 Infection and One Vaccination

We present here a 64-year-old male participant of the CoNAN study who experienced a PCR-confirmed mild SARS-CoV-2 infection but did not develop any measurable antibody response. Additionally, after vaccination with ChAdOx1 (AstraZeneca, Cambridge, UK) 11 months later, no antibodies were detected in six serological tests three weeks after the vaccination. When we assessed T-helper (Th) cell immunity, SARS-CoV-2-specific Th cells produced detectable amounts of IFNγ and TNF six weeks after the infection. A robust T-cell immunity remained detectable at least until six months after the infection and was boosted by the vaccination thereafter. This case report points out that an assessment of a prior infection or a vaccine response based solely on antibody detection might have limitations in individual patients.

Serum Cytokine Alterations Associated with Age of Patients with Nephropathia Epidemica

Nephropathia epidemica (NE) is a zoonotic disease caused by hantaviruses transmitted from rodents, endemic in the Republic of Tatarstan, Russia. The disease presents clinically with mild, moderate, and severe forms, and time-dependent febrile, oliguric, and polyuric stages of the disease are also recognized. The patient’s cytokine responses have been suggested to play a central role in disease pathogenesis; however, little is known about the different patterns of cytokine expression in NE in cohorts of different ages and sexes. Serum samples and clinical records were collected from 139 patients and 57 controls (healthy donors) and were used to analyze 48 analytes with the Bio-Plex multiplex magnetic bead-based antibody detection kits. Principal component analysis of 137 patient and 55 controls (for which there was full data) identified two components that individually accounted for >15% of the total variance in results and together for 38% of the total variance. PC1 represented a proinflammatory TH17/TH2 cell antiviral cytokine profile and PC2 a more antiviral cytokine profile with patients tending to display one or the other of these. Severity of disease and stage of illness did not show any correlation with PC1 profiles; however, significant differences were seen in patients with high PC1 profiles vs. lower for a number of individual clinical parameters: High PC1 patients showed a reduced number of febrile days, but higher maximum urine output, higher creatinine levels, and lower platelet levels. Overall, the results of this study point towards a stronger proinflammatory profile occurring in younger NE patients, this being associated with markers of acute kidney injury and low levels of high-density cholesterol. This is consistent with previous work indicating that the pathology of NE is immune driven, with an inflammatory immune response being associated with disease and that this immune response is more extreme in younger patients.

Spectral image contrast-based flow digital nanoplasmon-metry for ultrasensitive antibody detection

Background Gold nanoparticles (AuNPs) have been widely used in local surface plasmon resonance (LSPR) immunoassays for biomolecule sensing, which is primarily based on two conventional methods: absorption spectra analysis and colorimetry. The low figure of merit (FoM) of the LSPR and high-concentration AuNP requirement restrict their limit of detection (LOD), which is approximately ng to μg mL−1 in antibody detection if there is no other signal or analyte amplification. Improvements in sensitivity have been slow in recent for a long time, and pushing the boundary of the current LOD is a great challenge of current LSPR immunoassays in biosensing. Results In this work, we developed spectral image contrast-based flow digital nanoplasmon-metry (Flow DiNM) to push the LOD boundary. Comparing the scattering image brightness of AuNPs in two neighboring wavelength bands near the LSPR peak, the peak shift signal is strongly amplified and quickly detected. Introducing digital analysis, the Flow DiNM provides an ultrahigh signal-to-noise ratio and has a lower sample volume requirement. Compared to the conventional analog LSPR immunoassay, Flow DiNM for anti-BSA detection in pure samples has an LOD as low as 1 pg mL−1 within only a 15-min detection time and 500 μL sample volume. Antibody assays against spike proteins of SARS-CoV-2 in artificial saliva that contained various proteins were also conducted to validate the detection of Flow DiNM in complicated samples. Flow DiNM shows significant discrimination in detection with an LOD of 10 pg mL−1 and a broad dynamic detection range of five orders of magnitude. Conclusion Together with the quick readout time and simple operation, this work clearly demonstrated the high sensitivity and selectivity of the developed Flow DiNM in rapid antibody detection. Spectral image contrast and digital analysis further provide a new generation of LSPR immunoassay with AuNPs. Graphical Abstract

Lateral Flow Assay for the Detection of African Swine Fever Virus Antibodies Using Gold Nanoparticle-Labeled Acid-Treated p72

African swine fever is a widespread and highly contagious disease in the porcine population, which is caused by African swine fever virus (ASFV). The PCR and ELISA detection methods are the main conventional diagnostic methods for ASFV antigen/antibody detection in the field. However, these methods have limitations of expensive equipment, trained technicians, and time-consuming results. Thus, a rapid, inexpensive, accurate and on-site detection method is urgently needed. Here we describe a double-antigen-sandwich lateral-flow assay based on gold nanoparticle-conjugated ASFV major capsid protein p72, which can detect ASFV antibody in serum samples with high sensitivity and specificity in 10 min and the results can be determined by naked eyes. A lateral flow assay was established by using yeast-expressed and acid-treated ASFV p72 conjugated with gold nanoparticles, which are synthesized by seeding method. A high coincidence (97.8%) of the assay was determined using clinical serum compared to a commercial ELISA kit. In addition, our lateral flow strip can detect as far as 1:10,000 diluted clinically positive serum for demonstration of high sensitivity. In summary, the assay developed here was shown to be rapid, inexpensive, accurate and highly selective. It represents a reliable method for on-site ASFV antibody detection and may help to control the ASFV pandemic.

The utility of Coccidioides antigen and antibody detection in cerebrospinal fluid in the diagnosis of canine central nervous system coccidioidomycosis

OBJECTIVE To evaluate the utility of enzyme immunoassays (EIAs) for the detection of Coccidioides antigen and antibody in CSF in the diagnosis of CNS coccidioidomycosis in dogs. ANIMALS 51 dogs evaluated for CNS disease in a single specialty center in Tucson in 2016. PROCEDURES Excess CSF after routine analysis was banked after collection from dogs presented to the neurology service. Samples were tested by EIA for presence of Coccidioides antigen and antibody. Clinical data were collected from medical records retrospectively. RESULTS 22 dogs were diagnosed with CNS coccidioidomycosis (CCM) or another neurologic disease (non-CCM). These groups of dogs overlapped in the presenting complaints, MRI results, and routine CSF analysis results. Four dogs, all with CCM, had positive antigen EIA results. With clinical diagnosis used as the reference standard, CSF antigen testing had low sensitivity (20%) but high specificity (100%) for diagnosis of CCM. Ten dogs with CCM and 4 dogs with other diagnoses had antibody detected in CSF by EIA. Sensitivity of CSF antibody testing was 46%, specificity was 86%, and positive and negative predictive values for the study population were 71% and 68%, respectively. Clinical Relevance Diagnosis of CNS coccidioidomycosis in dogs in an endemic region was hampered by overlap of clinical signs with other neurologic disorders and the low sensitivity of confirmatory diagnostics. The evaluated Coccidioides-specific EIAs performed on CSF can aid in the diagnosis. A prospective study is warranted to corroborate and refine these preliminary findings